DS1722 Datasheet, PDF (5/14 Pages) Dallas Semiconductor – Digital Thermometer with SPI/3-Wire Interface

Temperature/Data Relationships Table 3
S
2⁶
2⁵
2⁴
2³
2²
MSb
(unit = °C)
2^-1
2^-2
2^-3
2^-4
0
0
DS1722
Address
Location
2¹
2⁰
02h
LSb
0
0
01h
TEMPERATURE
+120°C
+25.0625°C
+10.125°C
+0.5°C
0°C
-0.5°C
-10.125°C
-25.0625°C
-55°C
DIGITAL OUTPUT
(BINARY)
0111 1000 0000 0000
0001 1001 0001 0000
0000 1010 0010 0000
0000 0000 1000 0000
0000 0000 0000 0000
1111 1111 1000 0000
1111 0101 1110 0000
1110 0110 1111 0000
1100 1001 0000 0000
DIGITAL OUTPUT
(HEX)
7800h
1910h
0A20h
0080h
0000h
FF80h
F5E0h
E6F0h
C900h
OPERATION-Programming
The area of interest in programming the DS1722 is the Configuration register. All programming is done
via the SPI or 3-wire communication interface by selecting the appropriate address of the desired register
location. Table 4 illustrates the addresses for the two registers (configuration and temperature) of the
DS1722.
Register Address Structure Table 4
Read Address
Write Address
00h
80h
01h
No access
02h
No access
Active Register
Configuration
Temperature LSB
Temperature MSB
CONFIGURATION REGISTER PROGRAMMING
The configuration register is accessed in the DS1722 with the 00h address for reads and the 80h address
for writes. Data is read from or written to the configuration register MSb first for SPI communication and
LSb first for 3-wire communication. The format of the register is illustrated in Figure 2. The effect each
bit has on DS1722 functionality is described below along with the power-up state of the bit. The entire
register is volatile, and thus it will power-up in the default state.
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